I used to think extra weight was just a hassle, but man, having that heft behind the blade really does make a difference. It just powers through stuff you'd normally have to fight with. Totally worth it now that I've tried it.
Oh the weight thing, yeah I saw a documentary that said it was around 450 pounds. They had a whole segment on how they moved it, using these special rollers on a wooden track. Crazy to think about moving something that heavy without modern machinery.